Sensor

ABSTRACT

A magnetic sensor includes an insulating layer including a protruding surface, a first MR element, and a second MR element. The first MR element is disposed on a first inclined surface of the protruding surface. The second MR element is disposed on a second inclined surface of the protruding surface. The protruding surface includes first to third curved surface portions. Each of the second and third curved surface portions is a curved surface protruding in a direction closer to the top surface of the substrate.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 63/246,437 filed on Sep. 21, 2021 and Japanese PriorityPatent Application No. 2022-134778 filed on Aug. 26, 2022, the entirecontents of each of which are incorporated herein by their reference.

BACKGROUND

The technology relates to a sensor including sensor elements disposed ona protruding surface.

Magnetic sensors using magnetoresistive elements have been used forvarious applications in recent years. A system including a magneticsensor may be intended to detect a magnetic field containing a componentin a direction perpendicular to the surface of a substrate by using amagnetoresistive element provided on the substrate. In such a case, themagnetic field containing the component in the direction perpendicularto the surface of the substrate can be detected by providing a softmagnetic body for converting a magnetic field in the directionperpendicular to the surface of the substrate into a magnetic field inthe direction parallel to the surface of the substrate or locating themagnetoresistive element on an inclined surface formed on the substrate.

U.S. Patent Application Publication No. 2009/0027048 A1 discloses athree-axis magnetic sensor in which an X-axis sensor, a Y1-axis sensor,and a Y2-axis sensor are provided on a substrate. A plurality ofmagnetoresistive elements constituting the Y1-axis sensor and theY2-axis sensor are respectively formed on inclined surfaces of aplurality of protruding portions, each having a trapezoidal crosssection, formed on the substrate.

In a support member for supporting magnetoresistive elements, which hasa structure in which a plurality of trapezoidal protruding portionsprotrude from a flat portion, like the three-axis magnetic sensordisclosed in U.S. Patent Application Publication No. 2009/0027048 A1,the surface of each protruding portion and the surface of the flatportion are discontinuous at a boundary between the protruding portionand the flat portion. Therefore, the surface of the support member isnot smooth. In the magnetic sensor including the support member withsuch a structure, there may be a case where cracks are generated in thesupport member near the boundary between each protruding portion and theflat portion during a process of manufacturing the magnetic sensor orwhile the magnetic sensor is in use.

The foregoing problem is true of not only magnetic sensors but alsosensors in general that are obtained by forming sensor elements oninclined surfaces.

SUMMARY

A sensor according to one embodiment of the technology is a sensorconfigured to detect a predetermined physical quantity. The sensoraccording to one embodiment of the technology includes a substrateincluding a top surface, a support member disposed on the substrate, anda sensor element configured to change in a physical property dependingon a predetermined physical quantity. The support member includes aprotruding surface protruding in a direction away from the top surfaceof substrate and inclined at least partially with respect to the topsurface of the substrate. The protruding surface includes an upper endportion farthest from the top surface of the substrate. The sensorelement includes a functional layer constituting at least a part of thesensor element. The functional layer is disposed on the protrudingsurface. The protruding surface includes a first curved surface portionincluding the upper end portion, and a second curved surface portioncontinuous with the first curved surface portion and located between thefirst curved surface portion and the top surface of the substrate in adirection perpendicular to the top surface of the substrate. The secondcurved surface portion is a curved surface protruding in a directioncloser to the top surface of the substrate.

In the sensor according to one embodiment of the technology, the supportmember includes the protruding surface including the first curvedsurface portion and the second curved surface portion each having theforegoing feature. Thereby, according to one embodiment of thetechnology, it is possible to suppress the generation of cracks in asensor in which functional layers of sensor elements are formed on aninclined protruding surface.

Other and further objects, features and advantages of the technologywill appear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification. The drawings illustrate example embodimentsand, together with the specification, serve to explain the principles ofthe technology.

FIG. 1 is a perspective view showing a magnetic sensor according to anexample embodiment of the technology.

FIG. 2 is a functional block diagram showing a configuration of amagnetic sensor device including the magnetic sensor according to theexample embodiment of the technology.

FIG. 3 is a circuit diagram showing a circuit configuration of a firstdetection circuit of the example embodiment of the technology.

FIG. 4 is a circuit diagram showing a circuit configuration of a seconddetection circuit of the example embodiment of the technology.

FIG. 5 is a plan view showing a part of the magnetic sensor according tothe example embodiment of the technology.

FIG. 6 is a sectional view showing a part of the magnetic sensoraccording to the example embodiment of the technology.

FIG. 7 is a side view showing a magnetoresistive element of the exampleembodiment of the technology.

FIG. 8 is a sectional view showing a step of a method for manufacturingthe magnetic sensor according to the example embodiment of thetechnology.

FIG. 9 is a sectional view showing a step that follows the step shown inFIG. 8 .

FIG. 10 is a sectional view showing a step that follows the step shownin FIG. 9 .

FIG. 11 is a sectional view showing a step that follows the step shownin FIG. 10 .

FIG. 12 is an explanatory view for illustrating a shape of a supportmember of the example embodiment of the technology.

FIG. 13 is an explanatory view for illustrating a shape of a protrudingsurface of the example embodiment of the technology.

FIG. 14 is an explanatory chart showing a graph of a functionrepresenting the shape of the protruding surface of the exampleembodiment of the technology.

FIG. 15 is an explanatory chart showing a graph of a first derivative ofthe function shown in FIG. 14 .

FIG. 16 is an explanatory chart showing a graph of a second derivativeof the function shown in FIG. 14 .

DETAILED DESCRIPTION

An object of the technology is to provide a sensor in which functionallayers of sensor elements are formed on an inclined protruding surfaceand in which the generation of cracks can be suppressed.

In the following, some example embodiments and modification examples ofthe technology are described in detail with reference to theaccompanying drawings. Note that the following description is directedto illustrative examples of the disclosure and not to be construed aslimiting the technology. Factors including, without limitation,numerical values, shapes, materials, components, positions of thecomponents, and how the components are coupled to each other areillustrative only and not to be construed as limiting the technology.Further, elements in the following example embodiments which are notrecited in a most-generic independent claim of the disclosure areoptional and may be provided on an as-needed basis. The drawings areschematic and are not intended to be drawn to scale. Like elements aredenoted with the same reference numerals to avoid redundantdescriptions. Note that the description is given in the following order.

An example embodiment of the technology described below relates to asensor configured to detect a predetermined physical quantity. In theexample embodiment, the sensor includes sensor elements each configuredto change in a physical property depending on a predetermined physicalquantity. For example, the predetermined physical quantity may be atleast one of the direction or strength of a target magnetic field thatis a magnetic field to be detected. In such a case, the sensor elementsmay be magnetic detection elements each configured to detect a change inat least one of the direction or strength of the target magnetic field.The sensor including magnetic detection elements is also referred to asa magnetic sensor. The magnetic sensor is configured to detect at leastone of the direction or strength of the target magnetic field.Hereinafter, an example embodiment will be described in detail by takinga case where the sensor is a magnetic sensor as an example.

First, a configuration of a magnetic sensor according to an exampleembodiment of the technology will be described with reference to FIGS. 1and 2 . FIG. 1 is a perspective view showing a magnetic sensor accordingto the example embodiment. FIG. 2 is a functional block diagram showinga configuration of a magnetic sensor device including the magneticsensor according to the example embodiment. The magnetic sensor 1according to the example embodiment corresponds to the “sensor” of thetechnology.

As shown in FIG. 1 , the magnetic sensor 1 is in the form of a chiphaving a rectangular parallelepiped shape. The magnetic sensor 1includes a top surface 1 a and a bottom surface located opposite to eachother and also includes four side surfaces connecting the top surface 1a to the bottom surface. The magnetic sensor 1 also includes a pluralityof electrode pads disposed on the top surface 1 a.

Now, a description will be given of a reference coordinate system in thepresent example embodiment with reference to FIG. 1 . The referencecoordinate system is an orthogonal coordinate system that is set withreference to a magnetic sensor 1 and defined by three axes. An Xdirection, a Y direction, and a Z direction are defined in the referencecoordinate system. The X, Y, and Z directions are orthogonal to eachother. In particular, in the example embodiment, a direction that isperpendicular to the top surface 1 a of the magnetic sensor 1 and isoriented from the bottom surface to the top surface 1 a of the magneticsensor 1 is defined as the Z direction. The opposite directions to theX, Y, and Z directions will be expressed as −X, −Y, and −Z directions,respectively. The three axes defining the reference coordinate systemare an axis parallel to the X direction, an axis parallel to the Ydirection, and an axis parallel to the Z direction.

Hereinafter, the term “above” refers to positions located forward of areference position in the Z direction, and “below” refers to positionsopposite from the “above” positions with respect to the referenceposition. For each component of the magnetic sensor 1, the term “topsurface” refers to a surface of the component located at the end thereofin the Z direction, and “bottom surface” refers to a surface of thecomponent located at the end thereof in the −Z direction. The phrase“when seen in the Z direction” means that an object is seen from aposition at a distance in the Z direction.

As shown in FIG. 2 , the magnetic sensor 1 includes a first detectioncircuit 20 and a second detection circuit 30. Each of the first andsecond detection circuits 20 and 30 includes a plurality of magneticdetection elements, and is configured to detect a target magnetic fieldto generate at least one detection signal. In particular, in the exampleembodiment, the plurality of magnetic detection elements are a pluralityof magnetoresistive elements. The magnetoresistive elements willhereinafter be referred to as MR elements.

A plurality of detection signals generated by the first and seconddetection circuits 20 and 30 are processed by a processor 40. Themagnetic sensor 1 and the processor 40 constitute a magnetic sensordevice 100. The processor 40 is configured to, by processing theplurality of detection signals generated by the first and seconddetection circuits 20 and 30, generate a first detection value and asecond detection value respectively having correspondences withcomponents of a magnetic field in two different directions at apredetermined reference position. In particular, in the present exampleembodiment, the foregoing two different directions are a directionparallel to an XY plane and a direction parallel to the Z direction. Forexample, the processor 40 is constructed of an application-specificintegrated circuit (ASIC).

The processor 40 may be included in a support supporting the magneticsensor 1, for example. The support includes a plurality of electrodepads. The first and second detection circuits 20 and 30 are connected tothe processor 40 via the plurality of electrode pads of the magneticsensor 1, the plurality of electrode pads of the support, and aplurality of bonding wires, for example. In a case where the pluralityof electrode pads of the magnetic sensor 1 are provided on the topsurface 1 a of the magnetic sensor 1, the magnetic sensor 1 may bemounted on the top surface of the support in such a posture that thebottom surface of the magnetic sensor 1 faces the top surface of thesupport.

Next, the first and second detection circuits 20 and 30 will bedescribed with reference to FIGS. 3 to 6 . FIG. 3 is a circuit diagramshowing a circuit configuration of the first detection circuit 20. FIG.4 is a circuit diagram showing a circuit configuration of the seconddetection circuit 30. FIG. 5 is a plan view showing a part of themagnetic sensor 1. FIG. 6 is a sectional view showing a part of themagnetic sensor 1.

Here, as shown in FIG. 5 , a U direction and a V direction are definedas follows. The U direction is a direction rotated from the X directionto the −Y direction. The V direction is a direction rotated from the Ydirection to the X direction. More specifically, in the present exampleembodiment, the U direction is set to a direction rotated from the Xdirection to the −Y direction by α, and the V direction is set to adirection rotated from the Y direction to the X direction by α. Notethat α is an angle greater than 0° and smaller than 90°. For example, αis 45°. −U direction refers to a direction opposite to the U direction,and −V direction refers to a direction opposite to the V direction.

As shown in FIG. 6 , a W1 direction and a W2 direction are defined asfollows. The W1 direction is a direction rotated from the V direction tothe −Z direction. The W2 direction is a direction rotated from the Vdirection to the Z direction. More specifically, in the present exampleembodiment, the W1 direction is set to a direction rotated from the Vdirection to the −Z direction by β, and the W2 direction is set to adirection rotated from the V direction to the Z direction by β. Notethat β is an angle greater than 0° and smaller than 90°. −W1 directionrefers to a direction opposite to the W1 direction, and −W2 directionrefers to a direction opposite to the W2 direction. The W1 direction andW2 direction both are orthogonal to the U direction.

The first detection circuit 20 is configured to detect a component ofthe target magnetic field in a direction parallel to the W1 directionand generate at least one first detection signal which has acorrespondence with the component. The second detection circuit 30 isconfigured to detect a component of the target magnetic field in adirection parallel to the W2 direction and generate at least one seconddetection signal which has a correspondence with the component.

As shown in FIG. 3 , the first detection circuit 20 includes a powersupply port V2, a ground port G2, signal output ports E21 and E22, afirst resistor section R21, a second resistor section R22, a thirdresistor section R23, and a fourth resistor section R24. The pluralityof MR elements of the first detection circuit 20 constitute the first tofourth resistor sections R21, R22, R23, and R24.

The first resistor section R21 is provided between the power supply portV2 and the signal output port E21. The second resistor section R22 isprovided between the signal output port E21 and the ground port G2. Thethird resistor section R23 is provided between the signal output portE22 and the ground port G2. The fourth resistor section R24 is providedbetween the power supply port V2 and the signal output port E22.

As shown in FIG. 4 , the second detection circuit 30 includes a powersupply port V3, a ground port G3, signal output ports E31 and E32, afirst resistor section R31, a second resistor section R32, a thirdresistor section R33, and a fourth resistor section R34. The pluralityof MR elements of the second detection circuit 30 constitute the firstto fourth resistor sections R31, R32, R33, and R34.

The first resistor section R31 is provided between the power supply portV3 and the signal output port E31. The second resistor section R32 isprovided between the signal output port E31 and the ground port G3. Thethird resistor section R33 is provided between the signal output portE32 and the ground port G3. The fourth resistor section R34 is providedbetween the power supply port V3 and the signal output port E32.

A voltage or current of a predetermined magnitude is applied to each ofthe power supply ports V2 and V3. Each of the ground ports G2 and G3 isconnected to the ground.

The plurality of MR elements of the first detection circuit 20 will bereferred to as a plurality of first MR elements 50B. The plurality of MRelements of the second detection circuit 30 will be referred to as aplurality of second MR elements 50C. Since the first and seconddetection circuits 20 and 30 are the components of the magnetic sensor1, it can be said that the magnetic sensor 1 includes the plurality offirst MR elements 50B and the plurality of second MR elements 50C. Anygiven MR element will be denoted by the reference numeral 50.

FIG. 7 is a side view showing an MR element 50. The MR element 50 isspecifically a spin-valve MR element. The MR element 50 includes amagnetization pinned layer 52 having a magnetization whose direction isfixed, a free layer 54 having a magnetization whose direction isvariable depending on the direction of a target magnetic field, and agap layer 53 located between the magnetization pinned layer 52 and thefree layer 54. The MR element 50 may be a tunneling magnetoresistive(TMR) element or a giant magnetoresistive (GMR) element. In the TMRelement, the gap layer 53 is a tunnel barrier layer. In the GMR element,the gap layer 53 is a nonmagnetic conductive layer. The resistance ofthe MR element 50 changes with the angle that the magnetizationdirection of the free layer 54 forms with respect to the magnetizationdirection of the magnetization pinned layer 52. The resistance of the MRelement 50 is at its minimum value when the foregoing angle is 0°, andat its maximum value when the foregoing angle is 180°. In each MRelement 50, the free layer 54 has a shape anisotropy that sets thedirection of the magnetization easy axis to be orthogonal to themagnetization direction of the magnetization pinned layer 52. As amethod for setting the magnetization easy axis in a predetermineddirection in the free layer 54, a magnet configured to apply a biasmagnetic field to the free layer 54 can be used.

The MR element 50 further includes an antiferromagnetic layer 51. Theantiferromagnetic layer 51, the magnetization pinned layer 52, the gaplayer 53, and the free layer 54 are stacked in this order. Theantiferromagnetic layer 51 is formed of an antiferromagnetic material,and is in exchange coupling with the magnetization pinned layer 52 tothereby pin the magnetization direction of the magnetization pinnedlayer 52. The magnetization pinned layer 52 may be a so-calledself-pinned layer (Synthetic Ferri Pinned layer, SFP layer). Theself-pinned layer has a stacked ferri structure in which a ferromagneticlayer, a nonmagnetic intermediate layer, and a ferromagnetic layer arestacked, and the two ferromagnetic layers are antiferromagneticallycoupled. In a case where the magnetization pinned layer 52 is theself-pinned layer, the antiferromagnetic layer 51 may be omitted.

It should be appreciated that the layers 51 to 54 of each MR element 50may be stacked in the reverse order to that shown in FIG. 7 .

In FIGS. 3 and 4 , solid arrows represent the magnetization directionsof the magnetization pinned layers 52 of the MR elements 50. Hollowarrows represent the magnetization directions of the free layers 54 ofthe MR elements 50 in a case where no target magnetic field is appliedto the MR elements 50.

In the example shown in FIG. 3 , the magnetization directions of themagnetization pinned layers 52 in each of the first and third resistorsections R21 and R23 are the W1 direction. The magnetization directionsof the magnetization pinned layers 52 in each of the second and fourthresistor sections R22 and R24 are the −W1 direction. The free layer 54in each of the plurality of first MR elements 50B has a shape anisotropythat sets the direction of the magnetization easy axis to a directionparallel to the U direction. The magnetization directions of the freelayers 54 in each of the first and second resistor sections R21 and R22in a case where no target magnetic field is applied to the first MRelements 50B are the U direction. The magnetization directions of thefree layers 54 in each of the third and fourth resistor sections R23 andR24 in the foregoing case are the −U direction.

In the example shown in FIG. 4 , the magnetization directions of themagnetization pinned layers 52 in each of the first and third resistorsections R31 and R33 are the W2 direction. The magnetization directionsof the magnetization pinned layers 52 in each of the second and fourthresistor sections R32 and R34 are the −W2 direction. The free layer 54in each of the plurality of second MR elements 50C has a shapeanisotropy that sets the direction of the magnetization easy axis to adirection parallel to the U direction. The magnetization directions ofthe free layers 54 in each of the first and second resistor sections R31and R32 in a case where no target magnetic field is applied to thesecond MR element 50C are the U direction. The magnetization directionsof the free layers 54 in each of the third and fourth resistor sectionsR33 and R34 in the foregoing case are the −U direction.

The magnetic sensor 1 includes a magnetic field generator configured toapply a magnetic field in a predetermined direction to the free layer 54of each of the plurality of first MR elements 50B, and the plurality ofsecond MR elements 50C. In the present example embodiment, the magneticfield generator includes a coil 80 that applies a magnetic field in thepredetermined direction to the free layer 54 in each of the plurality offirst MR elements 50B and the plurality of second MR elements 50C.

Note that the magnetization directions of the magnetization pinnedlayers 52 and the directions of the magnetization easy axes of the freelayers 54 may slightly deviate from the foregoing directions from theperspective of the accuracy of the manufacturing of the MR elements 50and the like. The magnetization pinned layers 52 may be magnetized toinclude magnetization components having the foregoing directions astheir main components. In such a case, the magnetization directions ofthe magnetization pinned layers 52 are the same or substantially thesame as the foregoing directions.

Hereinafter, a specific structure of the magnetic sensor 1 will bedescribed in detail with reference to FIGS. 5 and 6 . FIG. 6 shows apart of a cross section at a position indicated by the line 6-6 in FIG.5 .

The magnetic sensor 1 includes a substrate 301 with a top surface 301 a,insulating layers 302, 303, 304, 305, 306, 307, 308, 309, and 310, aplurality of lower electrodes 61B, a plurality of lower electrodes 61C,a plurality of upper electrodes 62B, a plurality of upper electrodes62C, a plurality of lower coil elements 81, and a plurality of uppercoil elements 82. It is assumed that the top surface 301 a of thesubstrate 301 is parallel to the XY plane. The Z direction is also adirection perpendicular to the top surface 301 a of the substrate 301.The coil elements are a part of the coil winding.

The insulating layer 302 is disposed on the substrate 301. The pluralityof lower coil elements 81 are disposed on the insulating layer 302. Theinsulating layer 303 is disposed around the plurality of lower coilelements 81 on the insulating layer 302. The insulating layers 304, 305,and 306 are stacked in this order on the plurality of lower coilelements 81 and the insulating layer 303.

The plurality of lower electrodes 61B and the plurality of lowerelectrodes 61C are disposed on the insulating layer 306. The insulatinglayer 307 is disposed around the plurality of lower electrodes 61B andthe plurality of lower electrodes 61C on the insulating layer 306. Theplurality of first MR elements 50B are disposed on the plurality oflower electrodes 61B. The plurality of second MR elements 50C aredisposed on the plurality of lower electrodes 61C. The insulating layer308 is disposed around the plurality of first MR elements 50B and theplurality of second MR elements 50C on the plurality of lower electrodes61B, the plurality of lower electrodes 61C, and the insulating layer307. The plurality of upper electrodes 62B are disposed on the pluralityof first MR elements 50B and the insulating layer 308. The plurality ofupper electrodes 62C are disposed on the plurality of second MR elements50C and the insulating layer 308. The insulating layer 309 is disposedaround the plurality of upper electrodes 62B and the plurality of upperelectrodes 62C on the insulating layer 308.

The insulating layer 310 is disposed on the plurality of upperelectrodes 62B, the plurality of upper electrodes 62C, and theinsulating layer 309. The plurality of upper coil elements 82 aredisposed on the insulating layer 310. The magnetic sensor 1 may furtherinclude a not-shown insulating layer that covers the plurality of uppercoil elements 82 and the insulating layer 310.

The magnetic sensor 1 includes a support member supporting the pluralityof first MR elements 50B and the plurality of second MR elements 50C.The support member includes at least one inclined surface inclined withrespect to the top surface 301 a of the substrate 301. In particular, inthe example embodiment, the support member includes the insulating layer305. Note that FIG. 5 shows the insulating layer 305, the plurality offirst MR elements 50B, the plurality of second MR elements 50C, and theplurality of upper coil elements 82 among the components of the magneticsensor 1.

The insulating layer 305 includes a plurality of protruding surfaces 305c each protruding in a direction (the Z direction) away from the topsurface 301 a of the substrate 301. Each of the plurality of protrudingsurfaces 305 c extends in a direction parallel to the U direction. Theoverall shape of each of the protruding surfaces 305 c is asemi-cylindrical curved surface formed by moving the curved shape (archshape) of the protruding surface 305 c shown in FIG. 6 along thedirection parallel to the U direction. The plurality of protrudingsurfaces 305 c are arranged at predetermined intervals along a directionparallel to the V direction.

Each of the plurality of protruding surfaces 305 c includes an upper endportion farthest from the top surface 301 a of the substrate 301. In theexample embodiment, each of the upper end portions of the plurality ofprotruding surfaces 305 c extends in the direction parallel to the Udirection. Herein, focus is placed on a given protruding surface 305 cof the plurality of protruding surfaces 305 c. The protruding surface305 c includes a first inclined surface 305 a and a second inclinedsurface 305 b. The first inclined surface 305 a refers to the part ofthe protruding surface 305 c on the side of the V direction of the upperend portion of the protruding surface 305 c. The second inclined surface305 b refers to the part of the protruding surface 305 c on the side ofthe −V direction of the upper end portion of the protruding surface 305c. In FIG. 5 , a boundary between the first inclined surface 305 a andthe second inclined surface 305 b is indicated by a dotted line.

The upper end portion of the protruding surface 305 c may be theboundary between the first inclined surface 305 a and the secondinclined surface 305 b. In such a case, the dotted line shown in FIG. 5indicates the upper end portion of the protruding surface 305 c.

The top surface 301 a of the substrate 301 is parallel to the XY plane.Each of the first inclined surface 305 a and the second inclined surface305 b is inclined with respect to the top surface 301 a of the substrate301, that is, the XY plane. In a cross section perpendicular to the topsurface 301 a of the substrate 301, a distance between the firstinclined surface 305 a and the second inclined surface 305 b becomessmaller in a direction away from the top surface 301 a of the substrate301.

In the example embodiment, since two or more protruding surface 305 care present, the number of each of the first inclined surfaces 305 a andthe second inclined surfaces 305 b is also two or more. The insulatinglayer 305 includes the plurality of first inclined surfaces 305 a andthe plurality of second inclined surfaces 305 b.

The insulating layer 305 further includes a flat surface 305 d presentaround the plurality of protruding surfaces 305 c. The flat surface 305d is a surface parallel to the top surface 301 a of the substrate 301.Each of the plurality of protruding surfaces 305 c protrudes in the Zdirection from the flat surface 305 d. In the example embodiment, theplurality of protruding surfaces 305 c are disposed at predeterminedintervals. Thus, the flat surface 305 d is present between the twoprotruding surfaces 305 c adjoining in the V direction.

The insulating layer 305 includes a plurality of protruding portionseach protruding in the Z direction, and a flat portion present aroundthe plurality of protruding portions. Each of the plurality ofprotruding portions extends in the direction parallel to the U directionand includes the protruding surface 305 c. The plurality of protrudingportions are arranged at predetermined intervals in the directionparallel to the V direction. The thickness (the dimension in the Zdirection) of the flat portion is substantially constant.

Note that the insulating layer 304 has a substantially constantthickness (i.e., a dimension in the Z direction), and is formed alongthe bottom surface of the insulating layer 305. The insulating layer 306has a substantially constant thickness (i.e., a dimension in the Zdirection), and is formed along the top surface of the insulating layer305.

In particular, in the example embodiment, the insulating layer 305includes a first layer 3051 disposed on the insulating layer 304, and asecond layer 3052 disposed on the first layer 3051. The second layer3052 includes a plurality of portions separated from one another. Theinsulating layer 306 is disposed on a portion of the top surface of thefirst layer 3051 where the second layer 3052 is not disposed, and on thetop surface of the second layer 3052. Each of the plurality of firstinclined surfaces 305 a and the plurality of second inclined surfaces305 b is formed across the first layer 3051 and the second layer 3052.

The plurality of lower electrodes 61B are disposed on the plurality offirst inclined surfaces 305 a. The plurality of lower electrodes 61C aredisposed on the plurality of second inclined surfaces 305 b. Asdescribed above, since each of the first inclined surfaces 305 a and thesecond inclined surfaces 305 b is inclined with respect to the topsurface 301 a of the substrate 301, that is, the XY plane, each of thetop surfaces of the plurality of lower electrodes 61B and each of thetop surfaces of the plurality of lower electrodes 61C are also inclinedwith respect to the XY plane. Thus, it can be said that the plurality offirst MR elements 50B and the plurality of second MR elements 50C aredisposed on the inclined surfaces inclined with respect to the XY plane.The insulating layer 305 is a member for supporting each of theplurality of first MR elements 50B and the plurality of second MRelements 50C so as to allow such MR elements to be inclined with respectto the XY plane.

Note that in the example embodiment, the first inclined surfaces 305 aare curved surfaces. Therefore, the first MR elements 50B are curvedalong the curved surfaces (the first inclined surfaces 305 a). For thesake of convenience, in the present example embodiment, themagnetization directions of the magnetization pinned layers 52 of thefirst MR elements 50B are defined as straight directions as describedabove. The W1 direction and the −W1 direction that are the magnetizationdirections of the magnetization pinned layers 52 of the first MRelements 50B are also directions in which the tangents to the firstinclined surfaces 305 a at the vicinity of the first MR elements 50Bextend.

Similarly, in the example embodiment, the second inclined surfaces 305 bare curved surfaces. Therefore, the second MR elements 50C are curvedalong the curved surfaces (the second inclined surfaces 305 b). For thesake of convenience, in the present example embodiment, themagnetization directions of the magnetization pinned layers 52 of thesecond MR elements 50C are defined as straight directions as describedabove. The W2 direction and the −W2 direction that are the magnetizationdirections of the magnetization pinned layers 52 of the second MRelements 50C are also directions in which the tangents to the secondinclined surfaces 305 b at the vicinity of the second MR elements 50Cextend.

As shown in FIG. 5 , the plurality of first MR elements 50B are disposedso that two or more MR elements 50B are arranged both in the U directionand in the V direction. The plurality of first MR elements 50B arealigned in a row on one first inclined surface 305 a. Similarly, theplurality of second MR elements 50C are disposed so that two or more MRelements 50C are arranged both in the U direction and in the Vdirection. The plurality of second MR elements 50C are aligned in a rowon one second inclined surface 305 b. In the example embodiment, the rowof the plurality of first MR elements 50B and the row of the pluralityof second MR elements 50C are alternately arranged in the directionparallel to the V direction.

Note that one first MR element 50B and one second MR element 50Cadjoining each other may or may not deviate in the direction parallel tothe U direction when seen in the Z direction. Two first MR elements 50Badjoining each other across one second MR element 50C may or may notdeviate in the direction parallel to the U direction when seen in the Zdirection. Two second MR elements 50C adjoining each other across onefirst MR element 50B may or may not deviate in the direction parallel tothe U direction when seen in the Z direction.

The plurality of first MR elements 50B are connected in series by theplurality of lower electrodes 61B and the plurality of upper electrodes62B. Herein, a method for connecting the plurality of first MR elements50B will be described in detail with reference to FIG. 7 . In FIG. 7 ,the reference sign 61 denotes a lower electrode corresponding to a givenMR element 50, and the reference numeral 62 denotes an upper electrodecorresponding to the given MR element 50. As shown in FIG. 7 , eachlower electrode 61 has a long slender shape. Two lower electrodes 61adjoining in the longitudinal direction of the lower electrodes 61 havea gap therebetween. MR elements 50 are disposed near both longitudinalends on the top surface of each lower electrode 61. Each upper electrode62 has a long slender shape, and electrically connects two adjoining MRelements 50 that are disposed on two lower electrodes 61 adjoining inthe longitudinal direction of the lower electrodes 61.

Although not shown, one MR element 50 located at the end of a row of aplurality of aligned MR elements 50 is connected to another MR element50 located at the end of another row of a plurality of MR elements 50adjoining in a direction intersecting with the longitudinal direction ofthe lower electrodes 61. Such two MR elements 50 are connected to eachother by a not-shown electrode. The not-shown electrode may be anelectrode that connects the bottom surfaces or the top surfaces of thetwo MR elements 50.

In a case where the MR elements 50 shown in FIG. 7 are the first MRelements 50B, the lower electrodes 61 shown in FIG. 7 correspond to thelower electrodes 61B, and the upper electrodes 62 shown in FIG. 7correspond to the upper electrodes 62B. In such a case, the longitudinaldirection of the lower electrodes 61 is parallel to the U direction.

Similarly, the plurality of second MR elements 50C are connected inseries by the plurality of lower electrodes 61C and the plurality ofupper electrodes 62C. The foregoing description of the method forconnecting the plurality of first MR elements 50B holds true for themethod for connecting the plurality of second MR elements 50C. In a casewhere the MR elements 50 shown in FIG. 7 are the second MR elements 50C,the lower electrodes 61 shown in FIG. 7 correspond to the lowerelectrodes 61C, and the upper electrodes 62 shown in FIG. 7 correspondto the upper electrodes 62C. In such a case, the longitudinal directionof the lower electrodes 61 is parallel to the U direction.

Note that in the example embodiment, a stacked film including theantiferromagnetic layer 51, the magnetization pinned layer 52, the gaplayer 53, and the free layer 54 is described as the MR element 50.However, the MR element of the example embodiment may also be an elementincluding such a stacked film, the lower electrode 61, and the upperelectrode 62. The stacked film includes a plurality of magnetic films.The lower electrode 61 is a nonmagnetic metal layer disposed between theprotruding surface 305 c and the plurality of magnetic films. The MRelement may also include a plurality of stacked films, a plurality oflower electrodes 61, and a plurality of upper electrodes 62.

Each of the plurality of upper coil elements 82 extends in a directionparallel to the Y direction. The plurality of upper coil elements 82 arearranged in the X direction. In particular, in the present exampleembodiment, when seen in the Z direction, each of the plurality of firstMR elements 50B and the plurality of second MR elements 50C overlaps twoupper coil elements 82.

Each of the plurality of lower coil elements 81 extends in a directionparallel to the Y direction. The plurality of lower coil elements 81 arearranged in the X direction. The shape and arrangement of the pluralityof lower coil elements 81 may be the same as or different from those ofthe plurality of upper coil elements 82. In the example shown in FIGS. 5and 6 , the dimension in the X direction of each of the plurality oflower coil elements 81 is smaller than the dimension in the X directionof each of the plurality of upper coil elements 82. The distance betweentwo lower coil elements 81 adjoining in the X direction is smaller thanthe distance between two upper coil elements 82 adjoining in the Xdirection.

In the example shown in FIGS. 5 and 6 , the plurality of lower coilelements 81 and the plurality of upper coil elements 82 are electricallyconnected so as to constitute the coil 80 that applies a magnetic fieldin a direction parallel to the X direction to the free layer 54 in eachof the plurality of first MR elements 50B and the plurality of second MRelements 50C. Alternatively, the coil 80 may be configured to be ableto, for example, apply a magnetic field in the X direction to the freelayers 54 in the first and second resistor sections R21 and R22 of thefirst detection circuit 20 and the first and second resistor sectionsR31 and R32 of the second detection circuit 30, and apply a magneticfield in the −X direction to the free layers 54 in the third and fourthresistor sections R23 and R24 of the first detection circuit 20 and thethird and fourth resistor sections R33 and R34 of the second detectioncircuit 30. The coil 80 may be controlled by the processor 40.

Next, the first and second detection signals will be described. First,the first detection signal will be described with reference to FIG. 3 .As the strength of the component of the target magnetic field in thedirection parallel to the W1 direction changes, the resistance of eachof the resistor sections R21 to R24 of the first detection circuit 20changes either so that the resistances of the resistor sections R21 andR23 increase and the resistances of the resistor sections R22 and R24decrease or so that the resistances of the resistor sections R21 and R23decrease and the resistances of the resistor sections R22 and R24increase. Thereby the electric potential of each of the signal outputports E21 and E22 changes. The first detection circuit 20 generates asignal corresponding to the electric potential of the signal output portE21 as a first detection signal S21, and generates a signalcorresponding to the electric potential of the signal output port E22 asa first detection signal S22.

Next, the second detection signal will be described with reference toFIG. 4 . As the strength of the component of the target magnetic fieldin the direction parallel to the W2 direction changes, the resistance ofeach of the resistor sections R31 to R34 of the second detection circuit30 changes either so that the resistances of the resistor sections R31and R33 increase and the resistances of the resistor sections R32 andR34 decrease or so that the resistances of the resistor sections R31 andR33 decrease and the resistances of the resistor sections R32 and R34increase. Thereby the electric potential of each of the signal outputports E31 and E32 changes. The second detection circuit 30 generates asignal corresponding to the electric potential of the signal output portE31 as a second detection signal S31, and generates a signalcorresponding to the electric potential of the signal output port E32 asa second detection signal S32.

Next, the operation of the processor 40 will be described. The processor40 is configured to generate the first detection value and the seconddetection value based on the first detection signals S21 and S22 and thesecond detection signals S31 and S32. The first detection value is adetection value corresponding to the component of the target magneticfield in the direction parallel to the V direction. The second detectionvalue is a detection value corresponding to the component of the targetmagnetic field in the direction parallel to the Z direction. The firstdetection value is represented by a symbol Sv, and the second detectionvalue is represented by a symbol Sz.

The processor 40 generates the first and second detection values Sv andSz as follows, for example. First, the processor 40 generates a value S1by an arithmetic including obtainment of the difference S21−S22 betweenthe first detection signal S21 and the first detection signal S22, andgenerates a value S2 by an arithmetic including obtainment of thedifference S31−S32 between the second detection signal S31 and thesecond detection signal S32. Next, the processor 40 calculates values S3and S4 using the following expressions (1) and (2).

S3=(S2+S1)/(2 cos α)  (1)

S4=(S2−S1)/(2 sin α)  (2)

The first detection value Sv may be the value S3 itself, or may be aresult of a predetermined correction, such as a gain adjustment or anoffset adjustment, made to the value S3. In the same manner, the seconddetection value Sz may be the value S4 itself, or may be a result of apredetermined correction, such as a gain adjustment or an offsetadjustment, made to the value S4.

Next, a method for manufacturing the magnetic sensor 1 according to theexample embodiment will be described with reference to FIGS. 8 to 11 .FIGS. 8 to 11 each show a stack during a process of manufacturing themagnetic sensor 1. In the method for manufacturing the magnetic sensor1, first, the insulating layer 302 is formed on the substrate 301 asshown in FIG. 8 . Next, the plurality of lower coil elements 81, aconnection layer 83 of a conductive material, and the insulating layer303 are formed on the insulating layer 302. Next, the insulating layer304 is formed on the plurality of lower coil elements 81, the connectionlayer 83, and the insulating layer 303.

FIG. 9 shows the following step. In the step, the insulating layer 304is selectively etched so that an opening for exposing the top surface ofthe connection layer 83 is formed in the insulating layer 304. Next, ametal film 84 of a conductive material is formed on the top surface ofthe connection layer 83. Next, a connection layer 85 of a conductivematerial is formed on the metal film 84. Next, the first layer 3051 ofthe insulating layer 305 is formed around the connection layer 85.

FIG. 10 shows the following step. In the step, first, a metal film 86 ofa conductive material is formed on the top surface of the connectionlayer 85. Next, the second layer 3052 of the insulating layer 305 isformed on the metal film 86 and the first layer 3051 of the insulatinglayer 305.

FIG. 11 shows the following step. In the step, the first layer 3051 andthe second layer 3052 are etched so that the plurality of protrudingsurfaces 305 c are formed on the insulating layer 305. The plurality ofprotruding surfaces 305 c are formed by, for example, forming aplurality of etching masks on the second layer 3052 and then etching thefirst layer 3051, the second layer 3052, and the plurality of etchingmasks so as to remove the plurality of etching masks. The plurality ofetching masks have shapes corresponding to the plurality of protrudingsurfaces 305 c. A portion of the first layer 3051 not covered with theplurality of etching masks becomes the flat surface 305 d. During theetching, the metal film 86 functions as an etching stopper forprotecting the connection layer 85.

The connection layer 85 is a structure embedded in the first layer 3051.The connection layer 85 includes an end surface farthest from the topsurface 301 a of the substrate 301, that is, a top surface. The endsurface (top surface) of the connection layer 85 is disposed atsubstantially the same position as an interface between the first layer3051 and the second layer 3052 in the direction perpendicular to the topsurface 301 a of the substrate 301, that is, the direction parallel tothe Z direction.

Hereinafter, a step to be performed after the first layer 3051 and thesecond layer 3052 are etched will be described with reference to FIG. 6. First, the insulating layer 306 is formed on the first layer 3051 andthe second layer 3052. Next, the plurality of lower electrodes 61B, theplurality of lower electrodes 61C, the plurality of first MR elements50B, the plurality of second MR elements 50C, the plurality of upperelectrodes 62B, the plurality of upper electrodes 62C, and theinsulating layers 307 to 309 are formed on the insulating layer 306.

Next, the insulating layer 310 is formed on the plurality of upperelectrodes 62B, the plurality of upper electrodes 62C, and theinsulating layer 309. Next, the plurality of upper coil elements 82 areformed on the insulating layer 310. Thereby the magnetic sensor 1 iscompleted.

The connection layers 83 and 85 may be used as connection portions forconnecting the plurality of lower coil elements 81 and the plurality ofupper coil elements 82. In such a case, for example, after theinsulating layer 310 is formed and before the plurality of upper coilelements 82 are formed, the insulating layers 306 to 310 may beselectively etched to form an opening for exposing the metal film 86,and then, a not-shown connection layer of a conductive material may beformed in the opening. The plurality of upper coil elements 82 areformed to be connected to the not-shown connection layer after thenot-shown connection layer is formed.

Alternatively, the metal film 86 may be used as a given electrode pad(for example, an electrode pad of the coil 80). In such a case, forexample, a photoresist layer that covers the metal film 86 may be formedafter the first layer 3051 and the second layer 3052 are etched andbefore the insulating layer 306 is formed. The photoresist layer isremoved after the upper coil elements 82 are formed, for example.

Next, features of the structure of the magnetic sensor 1 according tothe example embodiment will be described. The magnetic sensor 1 includesthe substrate 301 with the top surface 301 a, the support memberdisposed on the substrate 301, the first MR elements 50B, and the secondMR elements 50C. In particular, in the example embodiment, theinsulating layer 305 corresponds to the support member. The plurality oflower coil elements 81 and the insulating layers 302 to 304 are disposedbetween the substrate 301 and the insulating layer 305. The insulatinglayer 305 includes the first inclined surfaces 305 a and the secondinclined surfaces 305 b.

Each of the first and second MR elements 50B and 50C includes at leasttwo magnetic films, that is, the magnetization pinned layer 52 and thefree layer 54. The two magnetic films of each first MR element 50B forma part (a main part) of the first MR element 50B. The two magnetic filmsof each second MR element 50C form a part (a main part) of the second MRelement 50C. Hereinafter, such two magnetic films will be referred to asfunctional layers. The functional layers of the first MR elements 50Bare disposed on the first inclined surfaces 305 a. The functional layersof the second MR elements 50C are disposed on the second inclinedsurfaces 305 b. The insulating layer 305 includes the first layer 3051and the second layer 3052 disposed on the first layer 3051. Each of thefirst layer 3051 and the second layer 3052 is formed of an insulatingmaterial, such as SiO₂.

Hereinafter, features of the first inclined surface 305 a, the secondinclined surface 305 b, the first layer 3051, and the second layer 3052will be described in detail with reference to FIG. 12 . FIG. 12 is anexplanatory view for illustrating the shape of the support member, thatis, the insulating layer 305.

Each of the first inclined surface 305 a and the second inclined surface305 b is formed across the first layer 3051 and the second layer 3052.The first inclined surface 305 a and the second inclined surface 305 bface different directions. Regarding one protruding surface 305 c, thefirst inclined surface 305 a and the second inclined surface 305 b maybe symmetrical about a virtual UZ plane perpendicular to the top surface301 a of the substrate 301.

From the perspective of reducing the height of the magnetic sensor 1,the dimension of each of the first inclined surface 305 a and the secondinclined surface 305 b in the direction perpendicular to the top surface301 a of the substrate 301, that is, the direction parallel to the Zdirection is preferably in the range from 1.4 μm or more to 3.0 μm orless.

The first inclined surface 305 a includes a first end edge 305 a 1closest to the top surface 301 a of the substrate 301, and a second endedge 305 a 2 farthest from the top surface 301 a of the substrate 301.The first end edge 305 a 1 is located in the first layer 3051. Thesecond end edge 305 a 2 is located in the second layer 3052.

The second inclined surface 305 b includes a first end edge 305 b 1closest to the top surface 301 a of the substrate 301, and a second endedge 305 b 2 farthest from the top surface 301 a of the substrate 301.The first end edge 305 b 1 is located in the first layer 3051. Thesecond end edge 305 b 2 is located in the second layer 3052. Note thatin the example shown in FIG. 12 , the second end edge 305 b 2 of thesecond inclined surface 305 b coincides with the second end edge 305 a 2of the first inclined surface 305 a.

The first layer 3051 includes a lower end portion 3051 a closest to thetop surface 301 a of the substrate 301, and an upper end portion 3051 bfarthest from the top surface 301 a of the substrate 301. The secondlayer 3052 includes a lower end portion 3052 a closest to the topsurface 301 a of the substrate 301, and an upper end portion 3052 bfarthest from the top surface 301 a of the substrate 301. The distancefrom the interface between the first layer 3051 and the second layer3052 to the lower end portion 3051 a of the first layer 3051 is shorterthan the distance from the interface between the first layer 3051 andthe second layer 3052 to the upper end portion 3052 b of the secondlayer 3052.

The first end edge 305 a 1 of the first inclined surface 305 a isdisposed between the lower end portion 3051 a and the upper end portion3051 b of the first layer 3051 in the direction perpendicular to the topsurface 301 a of the substrate 301, that is, the direction parallel tothe Z direction. The first end edge 305 b 1 of the second inclinedsurface 305 b is disposed between the lower end portion 3051 a and theupper end portion 3051 b of the first layer 3051 in the directionparallel to the Z direction.

The functional layers of the first MR elements 50B are disposed alongthe surface of the second layer 3052, but are not disposed along thesurface of the first layer 3051. The functional layers of the second MRelements 50C are disposed along the surface of the second layer 3052,but are not disposed along the surface of the first layer 3051.

In the example embodiment, the first inclined surface 305 a is a smoothcurved surface as a whole. The first inclined surface 305 a includes nostep at the position of a boundary between the first layer 3051 and thesecond layer 3052. Similarly, in the example embodiment, the secondinclined surface 305 b is a smooth curved surface as a whole. The secondinclined surface 305 b includes no step at the position of a boundarybetween the first layer 3051 and the second layer 3052.

Next, features of the protruding surface 305 c of the support member,that is, the insulating layer 305 will be described with reference toFIG. 13 . FIG. 13 is an explanatory view for illustrating the shape ofthe protruding surface 305 c. The insulating layer 305 includes theprotruding surface 305 c. The protruding surface 305 c protrudes in thedirection away from the top surface 301 a of the substrate 301. At leasta part of the protruding surface 305 c is inclined with respect to thetop surface 301 a of the substrate 301. In particular, in the exampleembodiment, the protruding surface 305 c includes the first inclinedsurface 305 a and the second inclined surface 305 b.

The protruding surface 305 c includes an upper end portion E1 farthestfrom the top surface 301 a of the substrate 301. The upper end portionE1 may coincide with the second end edge 305 a 2 of the first inclinedsurface 305 a and the second end edge 305 b 2 of the second inclinedsurface 305 b shown in FIG. 12 .

The dimension of the protruding surface 305 c in the directionperpendicular to the top surface 301 a of the substrate 301, that is,the direction parallel to the Z direction is the same as the dimensionof each of the first and second inclined surfaces 305 a and 305 b in thedirection parallel to the Z direction. In other words, the dimension ofthe protruding surface 305 c in the direction parallel to the Zdirection is preferably in the range from 1.4 μm or more to 3.0 μm orless. The dimension of the protruding surface 305 c in the directionparallel to the V direction is preferably greater than or equal to 3 μmand less than or equal to 16 μm, for example.

The protruding surface 305 c includes a first curved surface portion 305c 1 including the upper end portion E1, a second curved surface portion305 c 2, and a third curved surface portion 305 c 3. The second curvedsurface portion 305 c 2 is continuous with the first curved surfaceportion 305 c 1 at a position on the side of the V direction of thefirst curved surface portion 305 c 1, and is located between the firstcurved surface portion 305 c 1 and the top surface 301 a of thesubstrate 301 in the direction perpendicular to the top surface 301 a ofthe substrate 301. The third curved surface portion 305 c 3 iscontinuous with the first curved surface portion 305 c 1 at a positionon the side opposite to the second curved surface portion 305 c 2, thatis, a position on the side of the −V direction of the first curvedsurface portion 305 c 1, and is located between the first curved surfaceportion 305 c 1 and the top surface 301 a of the substrate 301 in thedirection perpendicular to the top surface 301 a of the substrate 301.Each of the second curved surface portion 305 c 2 and the third curvedsurface portion 305 c 3 is continuous with the flat surface 305 d.

The first curved surface portion 305 c 1 is a curved surface protrudingin the direction away from the top surface 301 a of the substrate 301.Each of the second curved surface portion 305 c 2 and the third curvedsurface portion 305 c 3 is a curved surface protruding in a directioncloser to the top surface 301 a of the substrate 301.

Herein, a cross section that is perpendicular to the top surface 301 aof the substrate 301 and is parallel to the VZ plane is referred to as areference cross section. The first curved surface portion 305 c 1 can beapproximated to an arc in the reference cross section. In FIG. 13 , theradius of curvature of the first curved surface portion 305 c 1 in thereference cross section, that is, the radius of curvature of an arc towhich the entire first curved surface portion 305 c 1 is approximated isrepresented by a symbol R1. The radius of curvature R1 is preferablygreater than or equal to 4.25 μm and less than or equal to 5.45 μm.

Similarly, each of the second curved surface portion 305 c 2 and thethird curved surface portion 305 c 3 can be approximated to an arc inthe reference cross section. In FIG. 13 , the radius of curvature of thesecond curved surface portion 305 c 2 in the reference cross section,that is, the radius of curvature of an arc to which the second curvedsurface portion 305 c 2 is approximated is represented by a symbol R2,and the radius of curvature of the third curved surface portion 305 c 3in the reference cross section, that is, the radius of curvature of anarc to which the third curved surface portion 305 c 3 is approximated isrepresented by a symbol R3. Each of the radii of curvature R2 and R3 ispreferably smaller than the radius of curvature R1 and greater than orequal to 0.3 μm.

Herein, the shape of the protruding surface 305 c in the reference crosssection is regarded as a function Z having as an independent variable aposition on a virtual straight line that is parallel to each of thereference cross section and the top surface 301 a of the substrate 301.The virtual straight line is parallel to the V direction. Hereinafter,the virtual straight line will be referred to as a V axis, and aposition on the V axis is represented by a symbol v. The function Z is afunction having v as an independent variable. The value of the functionZ corresponds to the position of the protruding surface 305 c in thedirection parallel to the Z direction. FIG. 14 shows a graph of thefunction Z. In FIG. 14 , the abscissa axis represents the position onthe V axis, and the ordinate axis represents the value of the functionZ. FIG. 14 substantially shows the shape of the protruding surface 305 cin the reference cross section.

Note that in FIG. 14 , a position on the V axis corresponding to theupper end portion E1 of the protruding surface 305 c is set as theorigin (0 μm) on the abscissa axis, and a position on the side of the Vdirection with respect to the origin is represented by a positive value,while a position on the side of the −V direction with respect to theorigin is represented by a negative value. In FIG. 14 , the position ofthe flat surface 305 d in the direction parallel to the Z direction is 0μm.

FIG. 15 shows a graph of a first derivative Z′ (dZ/dv) obtained bydifferentiating the function Z once using the variable v. In FIG. 15 ,the abscissa axis represents the position on the V axis, and theordinate axis represents the value of the first derivative Z′. FIG. 16shows a graph of a second derivative Z″ (d²Z/dv²) obtained bydifferentiating the function Z twice using the variable v. In FIG. 15 ,the abscissa axis represents the position on the V axis, and theordinate axis represents the value of the second derivative Z″.

Two positions where the second derivative Z″ is 0 respectively representa position on the V axis corresponding to a boundary between the firstcurved surface portion 305 c 1 and the second curved surface portion 305c 2 and a position on the V axis corresponding to a boundary between thefirst curved surface portion 305 c 1 and the third curved surfaceportion 305 c 3. Thus, referring to FIG. 16 can identify the position ofeach of the first to third curved surface portions 305 c 1 to 305 c 3.FIGS. 14 to 16 show the general range of each of the first to thirdcurved surface portions 305 c 1 to 305 c 3.

As shown in FIG. 16 , at a position on the V axis corresponding to thefirst curved surface portion 305 c 1, the value of the second derivativeZ″ is less than or equal to 0. At a position on the V axis correspondingto the second curved surface portion 305 c 2 and at a position on the Vaxis corresponding to the third curved surface portion 305 c 3, thevalue of the second derivative Z″ is a positive value.

Herein, as shown in FIG. 16 , the first curved surface portion 305 c 1is divided into a first portion c11, a second portion c12, and a thirdportion c13. The first portion c11 is a portion including the upper endportion E1 of the protruding surface 305 c. The second portion c12 is aportion continuous with the first portion c11 at a position away fromthe upper end portion E1 of the protruding surface 305 c and on the sideof the V direction of the first portion c11. The third portion c13 is aportion continuous with the first portion c11 at a position away fromthe upper end portion E1 of the protruding surface 305 c and on the sideof the −V direction of the first portion c11. The second portion c12 islocated below (on the side of the −Z direction of) the first MR element50B. The third portion c13 is located below (on the side of the −Zdirection of) the second MR element 50C. The first and second MRelements 50B and 50C are not present above (on the side of the Zdirection of) the first portion c11. FIG. 16 shows the general range ofeach of the first to third portions c11 to c13.

The mean value of the absolute value of the second derivative Z″ of thefunction Z corresponding to the first portion c11 is smaller than themean value of the absolute value of the second derivative Z″ of thefunction Z corresponding to the second portion c12. Similarly, the meanvalue of the absolute value of the second derivative Z″ of the functionZ corresponding to the first portion c11 is smaller than the mean valueof the absolute value of the second derivative Z″ of the function Zcorresponding to the third portion c13.

In the example embodiment, the value of the first derivative Z′ of thefunction Z corresponding to the first curved surface portion 305 c 1decreases or increases in a direction closer to one end of the firstcurved surface portion 305 c 1 in the direction parallel to the Vdirection from the other end of the first curved surface portion 305 c 1in the direction parallel to the V direction. In other words, the valueof the first derivative Z′ becomes smaller in a direction closer to anend portion of the first curved surface portion 305 c 1 on the side ofthe V direction from an end portion of the first curved surface portion305 c 1 on the side of the −V direction. Alternatively, the value of thefirst derivative Z′ becomes greater in a direction closer to the endportion of the first curved surface portion 305 c 1 on the side of the−V direction from the end portion of the first curved surface portion305 c 1 on the side of the V direction.

Next, operations and effects of the magnetic sensor 1 according to theexample embodiment will be described. In the example embodiment, thesupport member, that is, the insulating layer 305 includes the firstlayer 3051 and the second layer 3052, and also includes the first andsecond inclined surfaces 305 a and 305 b formed across the first layer3051 and the second layer 3052. Herein, a case is considered where astructure of a metallic material is embedded in a support member, whichincludes only a single insulating layer, of a Comparative Example. Inthe support member of the Comparative Example, if an inclined surface isformed on the support member by etching, the structure greatly protrudesbeyond the surfaces formed by the etching due to the difference in theetching rates. In such a case, a problem would arise that it becomesdifficult to perform patterning on some electrodes or MR elements formedon the inclined surface due to the influence of the shadow of thestructure, for example.

In contrast, in the example embodiment, for example, the first inclinedsurface 305 a and the second inclined surface 305 b can be formed on theinsulating layer 305 in such a state that a structure is embedded in thefirst layer 3051 and no structure is embedded in the second layer 3052.Thereby, according to the example embodiment, the amount of protrusionof the structure can be suppressed in comparison with the support memberof the Comparative Example.

Note that the insulating material of the first layer 3051 and theinsulating material of the second layer 3052 may be the same ordifferent. In addition, film formation conditions of the first layer3051 and film formation conditions of the second layer 3052 may be thesame or different. For example, it is possible to, by varying at leastone of the insulating materials or the film formation conditions of thefirst layer 3051 and the second layer 3052 from each other, vary theshape of a part of the protruding surface 305 c formed on the firstlayer 3051 and the shape of another part of the protruding surface 305 cformed on the second layer 3052 from each other.

In the example embodiment, the protruding surface 305 c includes thefirst to third curved surface portions 305 c 1 to 305 c 3 each havingthe foregoing shape. If the second and third curved surface portions 305c 2 and 305 c 3 are not present, the flat surface 305 d and the firstcurved surface portion 305 c 1 become discontinuous at a boundarybetween the flat surface 305 d and the first curved surface portion 305c 1. Therefore, the surface of the insulating layer 305 does not becomesmooth. In contrast, in the example embodiment, since the protrudingsurface 305 c includes the second and third curved surface portions 305c 2 and 305 c 3, the surface of the insulating layer 305 can be madesmooth. Thereby, according to the example embodiment, it is possible tosuppress the generation of cracks in the insulating layer 305 near aboundary between the protruding surface 305 c and the flat surface 305d.

As described above, the radius of curvature R1 of the first curvedsurface portion 305 c 1 of the protruding surface 305 c differs from theradius of curvature R2 of the second curved surface portion 305 c 2 ofthe protruding surface 305 c and the radius of curvature R3 of the thirdcurved surface portion 305 c 3 of the protruding surface 305 c. At leasta part of the first curved surface portion 305 c 1 is formed on thesecond layer 3052. At least a part of each of the second and thirdcurved surface portions 305 c 2 and 305 c 3 is formed on the first layer3051. According to the example embodiment, it is possible toindividually adjust the etching rate of the first layer 3051 and theetch rate of the second layer 3052 by varying at least one of theinsulating materials or the film formation conditions of the first layer3051 and the second layer 3052 from each other, for example. Thereby,according to the example embodiment, it is possible to easily adjust theradii of curvature R2 and R3 to a preferable range while adjusting theradius of curvature R1 to a preferable range.

In particular, in the example embodiment, adjusting the radii ofcurvature R2 and R3 to the foregoing range can suppress the generationof cracks in the insulating layer 305 near the boundary between theprotruding surface 305 c and the flat surface 305 d in comparison withwhen the second and third curved surface portions 305 c 2 and 305 c 3are not present or when the radii of curvature are small to such anextent that the boundary between the protruding surface 305 c and theflat surface 305 d can be regarded as discontinuous.

Note that in the example embodiment, as understood from FIG. 16 , thevalue of the second derivative Z″ of the function Z corresponding to thefirst curved surface portion 305 c 1 is not constant. Therefore, in astrict sense, the radius of curvature R1 varies depending on theposition on the V axis. In particular, in the example embodiment, themean value of the absolute value of the second derivative Z″ of thefunction Z corresponding to the first portion c11 of the first curvedsurface portion 305 c 1 is smaller than the mean value of the absolutevalue of the second derivative Z″ of the function Z corresponding to thesecond portion c12 of the first curved surface portion 305 c 1 and themean value of the absolute value of the second derivative Z″ of thefunction Z corresponding to the third portion c13 of the first curvedsurface portion 305 c 1. Therefore, in the example embodiment, theradius of curvature R1 at the first portion c11 is greater than theradius of curvature R1 at the second portion c12 and the radius ofcurvature R1 at the third portion c13. Thereby, according to the exampleembodiment, it is possible to reduce the dimension of the protrudingsurface 305 c in the direction parallel to the Z direction, that is,reduce the height of the protruding surface 305 c in comparison withwhen the radius of curvature R1 is constant irrespective of the positionon the V axis.

In the example embodiment, the dimension of the protruding surface 305 cin the direction parallel to the Z direction is preferably in the rangefrom 1.4 μm or more to 3.0 μm or less. According to the exampleembodiment, setting the dimension of the protruding surface 305 c togreater than or equal to 1.4 μm can increase the inclination of each ofthe first inclined surface 305 a and the second inclined surface 305 band thus enhance the sensitivity of the magnetic sensor 1 to thecomponent of the target magnetic field in the direction parallel to theZ direction. Consequently, according to the example embodiment, thesecond detection value Sz can be generated with high accuracy. Inaddition, according to the example embodiment, setting the dimension ofthe protruding surface 305 c to less than or equal to 3.0 μm can form aphotoresist mask including a photoresist layer with high accuracy on thefirst inclined surface 305 a and the second inclined surface 305 bduring the process of manufacturing the magnetic sensor 1.

The technology is not limited to the foregoing example embodiment, andvarious modifications may be made thereto. For example, the magneticdetection elements are not limited to MR elements, and may be otherelements such as Hall elements that detect a magnetic field.

The support member, that is, the insulating layer 305 of the technologymay include only a single insulating layer. The description of theinsulating layer 305 holds true for such a single insulating layerexcept the description of the first layer 3051 and the second layer3052.

The support member of the technology may also include the insulatinglayer 305 and the insulating layer 306. In such a case, the supportmember includes a plurality of protruding surfaces and a flat surface.The plurality of protruding surfaces and the flat surface are formed bythe top surface of the insulating layer 306. The top surface of theinsulating layer 306 is similar to or almost similar to the top surfaceof the insulating layer 305. Thus, the plurality of protruding surfacesformed by the top surface of the insulating layer 306 are similar to oralmost similar to the plurality of protruding surfaces 305 c of theinsulating layer 305. The description of the shapes and arrangement ofthe plurality of protruding surfaces 305 c holds true for the pluralityof protruding surfaces formed by the top surface of the insulating layer306 except the description of the first layer 3051 and the second layer3052. Specifically, the description of the dimension of the protrudingsurfaces 305 c, the description of the radii of curvature R1 to R3, andthe description of the function Z, the first derivative Z′, and thesecond derivative Z″ hold true for the plurality of protruding surfacesformed by the top surface of the insulating layer 306.

The magnetic sensor 1 may further include a third detection circuitconfigured to detect a component of the target magnetic field in adirection parallel to the XY plane, and generate at least one thirddetection signal having a correspondence with the component. In such acase, the processor 40 may be configured to generate a detection valuecorresponding to a component of the target magnetic field in thedirection parallel to the U direction based on the at least one thirddetection signal. The third detection circuit may be integrated with thefirst and second detection circuits 20 and 30, or may be included in achip separate from the first and second detection circuits 20 and 30.

Each sensor element of the technology is not limited to a magneticdetection element, and may be a sensor element configured to change in aphysical property depending on a predetermined physical quantity. Thepredetermined physical quantity may be the quantity of the state of anyphysical phenomenon that can be detected by the sensor element, such asnot only a magnetic field but also an electric field, temperature,displacement, and force. The foregoing description of the exampleembodiment holds true for, other than a magnetic sensor, a sensorincluding sensor elements other than magnetic detection elements if themagnetic detection elements are replaced with the sensor elements. Insuch a case, the functional layers may be a portion that constitutes atleast a part of each sensor element and changes in a physical propertydepending on a predetermined physical quantity. In such a case, themetal layer may be any wiring layer.

As described above, the sensor according to one embodiment of thetechnology is a sensor configured to detect a predetermined physicalquantity. The sensor according to one embodiment of the technologyincludes a substrate including a top surface, a support member disposedon the substrate, and a sensor element configured to change in aphysical property depending on a predetermined physical quantity. Thesupport member includes a protruding surface protruding in the directionaway from the top surface of the substrate and inclined at leastpartially with respect to the top surface of the substrate. Theprotruding surface includes an upper end portion farthest from the topsurface of the substrate. Each sensor element includes functional layersconstituting at least a part of the sensor element. The functionallayers are disposed on the protruding surface. The protruding surfaceincludes a first curved surface portion including the upper end portion,and a second curved surface portion continuous with the first curvedsurface portion and located between the first curved surface portion andthe top surface of the substrate in the direction perpendicular to thetop surface of the substrate. The second curved surface portion is acurved surface protruding in the direction closer to the top surface ofthe substrate.

In the sensor according to one embodiment of the technology, the radiusof curvature of the second curved surface portion in a cross sectionperpendicular to the top surface of the substrate may be smaller thanthe radius of curvature of the first curved surface portion in the crosssection perpendicular to the top surface of the substrate, and may begreater than or equal to 0.3 μm.

In the sensor according to one embodiment of the technology, the firstcurved surface portion may be a curved surface protruding in thedirection away from the top surface of the substrate. The radius ofcurvature of the first curved surface portion in the cross sectionperpendicular to the top surface of the substrate may be greater than orequal to 4.25 μm and less than or equal to 5.45 μm.

In the sensor according to one embodiment of the technology, theprotruding surface may further include a third curved surface portioncontinuous with the first curved surface portion on a side opposite tothe second curved surface portion and located between the first curvedsurface portion and the top surface of the substrate in the directionperpendicular to the top surface of the substrate. The third curvedsurface portion may be a curved surface protruding in the directioncloser to the top surface of the substrate. In a case where the firstcurved surface portion is a curved surface protruding in the directionaway from the top surface of the substrate, the radius of curvature ofthe third curved surface portion in the cross section perpendicular tothe top surface of the substrate may be smaller than the radius ofcurvature of the first curved surface portion in the cross sectionperpendicular to the top surface of the substrate, and may be greaterthan or equal to 0.3 μm.

In the sensor according to one embodiment of the technology, the supportmember may further include a flat surface continuous with the protrudingsurface and parallel to the top surface of the substrate.

In the sensor according to one embodiment of the technology, thedimension of the protruding surface in the direction perpendicular tothe top surface of the substrate may be greater than or equal to 1.4 μmand less than or equal to 3.0 μm.

In the sensor according to one embodiment of the technology, thepredetermined physical quantity may be at least one of the direction orstrength of the target magnetic field. Each sensor element may be amagnetic detection element configured to detect a change in at least oneof the direction or strength of the target magnetic field. The magneticdetection element may be a magnetoresistive element. The functionallayers may include a plurality of magnetic films. The magnetoresistiveelement may further include a nonmagnetic metal layer disposed betweenthe protruding surface and the plurality of magnetic films.

Obviously, various modification examples and variations of thetechnology are possible in the light of the above teachings. Thus, it isto be understood that, within the scope of the appended claims andequivalents thereof, the technology may be practiced in otherembodiments than the foregoing example embodiment.

What is claimed is:
 1. A sensor configured to detect a predeterminedphysical quantity, comprising: a substrate including a top surface; asupport member disposed on the substrate; and a sensor elementconfigured to change in a physical property depending on thepredetermined physical quantity, wherein the support member includes aprotruding surface protruding in a direction away from the top surfaceof the substrate and inclined at least partially with respect to the topsurface of the substrate, the protruding surface includes an upper endportion farthest from the top surface of the substrate, the sensorelement includes a functional layer constituting at least a part of thesensor element, the functional layer is disposed on the protrudingsurface, the protruding surface includes a first curved surface portionincluding the upper end portion, and a second curved surface portioncontinuous with the first curved surface portion and located between thefirst curved surface portion and the top surface of the substrate in adirection perpendicular to the top surface of the substrate, and thesecond curved surface portion is a curved surface protruding in adirection closer to the top surface of the substrate.
 2. The sensoraccording to claim 1, wherein a radius of curvature of the second curvedsurface portion in a cross section perpendicular to the top surface ofthe substrate is smaller than a radius of curvature of the first curvedsurface portion in the cross section perpendicular to the top surface ofthe substrate, and is greater than or equal to 0.3 μm.
 3. The sensoraccording to claim 1, wherein the first curved surface portion is acurved surface protruding in the direction away from the top surface ofthe substrate.
 4. The sensor according to claim 3, wherein a radius ofcurvature of the first curved surface portion in a cross sectionperpendicular to the top surface of the substrate is greater than orequal to 4.25 μm and less than or equal to 5.45 μm.
 5. The sensoraccording to claim 1, wherein the protruding surface further includes athird curved surface portion continuous with the first curved surfaceportion on a side opposite to the second curved surface portion andlocated between the first curved surface portion and the top surface ofthe substrate in the direction perpendicular to the top surface of thesubstrate, and the third curved surface portion is a curved surfaceprotruding in the direction closer to the top surface of the substrate.6. The sensor according to claim 5, wherein the first curved surfaceportion is a curved surface protruding in the direction away from thetop surface of the substrate, and a radius of curvature of the thirdcurved surface portion in a cross section perpendicular to the topsurface of the substrate is smaller than a radius of curvature of thefirst curved surface portion in the cross section perpendicular to thetop surface of the substrate, and is greater than or equal to 0.3 μm. 7.The sensor according to claim 1, wherein the support member furtherincludes a flat surface continuous with the protruding surface andparallel to the top surface of the substrate.
 8. The sensor according toclaim 1, wherein a dimension of the protruding surface in the directionperpendicular to the top surface of the substrate is greater than orequal to 1.4 μm and less than or equal to 3.0 μm.
 9. The sensoraccording to claim 1, wherein the predetermined physical quantity is atleast one of a direction or a strength of a target magnetic field, andthe sensor element is a magnetic detection element configured to detecta change in at least one of the direction or the strength of the targetmagnetic field.
 10. The sensor according to claim 9, wherein themagnetic detection element is a magnetoresistive element, and thefunctional layer includes a plurality of magnetic films.
 11. The sensoraccording to claim 10, wherein the magnetoresistive element furtherincludes a nonmagnetic metal layer disposed between the protrudingsurface and the plurality of magnetic films.